"Failed to generate profile as curves do not precisely overlap" in sketch

[Max_Marz]

Hey all,

Just wanted to throw this weird behavior out there. I've got a empty component in a larger assembly that I'm getting ready to extrude into a body and I noticed it wasn't letting me select a face between a pair of concentric circles for extrusion.

I've attached the F3z file here, under the "spindle" component it is the only sketch.
Whenever I create a circle, in this case the two 5" and 6" diameter circles I get the above warning "failed to generate profile as curves do not precisely overlap." Kinda hard to imagine how that's possible given I'm creating a circle lol.

I'm sure if I re-create the sketch it will work fine but I just wanted to throw this up incase it helps with development or someone can tell me exactly what's going on.

[Max_Marz]

Soooo, I noticed that when re-creating the sketch if I draw the two concentric circles first it works no problem, as soon as I try to project the cylindrical "OD" face of the four corner tubes on the truss into the sketch, it breaks the profiles and they become no longer selectable/closed.

[HughesTooling · Accepted solution]

Projecting the surface is not a good idea as you end up with several overlapping circles.

In this situation best to use intersect.

[HughesTooling]

After enabling Show Projected geometry and window selecting and deleting all the small circles then intersecting it works correctly. @jeff_strater  Should hidden projected geometry affect the generation of profiles?

[Max_Marz]

Yeah after projecting just one of the tube edges it works fine, its just weird to me that the projection of the surface breaks the profiles and... OH WOW, why haven't I been using intersect... thank you sir. 

[HughesTooling]

When you project the surface you are also generating all the intersection and these are quite complex curves. Also they will be closed overlapping splines and you are just overloading the solver. The closed splines are a big problem and probably should flag an error.

If I break the link to for the projected geometry and select with the move tool it list 3,333 items selected! This is going to be a problem.

[Max_Marz]

Thank you sir, I was not aware of the difference between project and intersect.
Much appreciated.

[jeff_strater]

@HughesTooling - yes, that is intentional.  It's the same state as projected geometry from the sketch plane itself (which is always hidden, but still participates in profiles).  Whether that is desirable or not is another question, but yes, it is by design...